AQA · GCSE · Combined Science
Course version: 8464 · Version from Sept 2018
Waste management: in air, from smoke and acidic gases
Air pollution occurs when smoke particles and acidic gases enter the atmosphere.
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Air pollution occurs when smoke particles and acidic gases enter the atmosphere. Smoke consists of tiny solid particles and unburnt carbon from incomplete combustion of fuels; these particles can cause breathing problems and reduce visibility, and they may deposit as soot. Acidic gases include sulfur dioxide, formed when sulfur impurities in fuels burn, and nitrogen oxides, formed when nitrogen and oxygen react at high temperatures in engines. These gases dissolve in rainwater to form acid rain, which can damage trees, acidify lakes and corrode limestone buildings. For example, burning coal releases sulfur dioxide, which contributes to acid rain and harms aquatic life. Reducing emissions involves cleaner fuels, catalytic converters, scrubbers and renewable energy.
What earns the marks
- Identify smoke as particles from incomplete combustion that can harm the respiratory system and reduce air quality.
- Name sulfur dioxide as an acidic gas produced when fuels containing sulfur impurities are burned.
- Name nitrogen oxides as acidic gases formed when nitrogen and oxygen react at high temperatures, for example in vehicle engines.
- Explain that acidic gases dissolve in rainwater to form acid rain, which can damage trees, acidify lakes and corrode limestone or metal structures.
- Link each pollutant to a named source and a specific consequence rather than describing air pollution generally.
- Suggest a control measure, such as using cleaner fuels, fitting catalytic converters or using scrubbers to remove acidic gases.
Common mistakes and how to put them right
Confusing smoke with acidic gases.
Put it right: Classify each pollutant correctly.
Stating that acid rain directly kills trees by burning them.
Put it right: Describe indirect and direct effects accurately.
Claiming that carbon dioxide is the main acidic gas in acid rain.
Put it right: Name sulfur dioxide and nitrogen oxides.
Exam tips
- Distinguish clearly between smoke particles and acidic gases, giving a separate source and effect for each.
- Use the phrase incomplete combustion when explaining how smoke particles are produced.
- When describing acid rain, name at least one specific effect on ecosystems or materials to secure the explanation.
Try the lesson
The start of the Waste management: in air, from smoke and acidic gases lesson, made from checked teaching notes for this specification point.
Have a go first
Burning waste can release smoke and acidic gases into the air. Which of these is an acidic gas released when waste is burned?
Listen
Air pollution occurs when smoke particles and acidic gases enter the atmosphere. Smoke consists of tiny solid particles and unburnt carbon from incomplete combustion of fuels; these particles can cause breathing problems and reduce visibility, and they may deposit as soot. Acidic gases include sulfur dioxide, formed when sulfur impurities in fuels burn, and nitrogen oxides, formed when nitrogen and oxygen react at high temperatures in engines. These gases dissolve in rainwater to form acid rain, which can damage trees, acidify lakes and corrode limestone buildings. For example, burning coal releases sulfur dioxide, which contributes to acid rain and harms aquatic life. Reducing emissions involves cleaner fuels, catalytic converters, scrubbers and renewable energy. A strong answer earns marks for these points. Identify smoke as particles from incomplete combustion that can harm the respiratory system and reduce air quality. Name sulfur dioxide as an acidic gas produced when fuels containing sulfur impurities are burned. Name nitrogen oxides as acidic gases formed when nitrogen and oxygen react at high temperatures, for example in vehicle engines. Explain that acidic gases dissolve in rainwater to form acid rain, which can damage trees, acidify lakes and corrode limestone or metal structures. A common slip: Confusing smoke with acidic gases: smoke is particulate, whereas sulfur dioxide and nitrogen oxides are gases. Instead, classify each pollutant correctly. Exam tip: Distinguish clearly between smoke particles and acidic gases, giving a separate source and effect for each.
See it
Key words
Say what each word means before you turn the card.
Smoke
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Sulfur dioxide
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Nitrogen oxides
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Acid rain
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See every definition
- Smoke
- Tiny solid particles and unburnt carbon from incomplete combustion of fuels, which can cause breathing problems, reduce visibility and deposit as soot.
- Sulfur dioxide
- An acidic gas formed when sulfur impurities in fuels burn, which dissolves in rainwater to form acid rain.
- Nitrogen oxides
- Acidic gases formed when nitrogen and oxygen react at high temperatures in engines, which dissolve in rainwater to form acid rain.
- Acid rain
- Formed when acidic gases dissolve in rainwater, and can damage trees, acidify lakes and corrode limestone buildings.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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